A state highway has been closed after a serious crash involving two cars in the Hauraki area this afternoon.

Few details were immediately available on the crash in the Karangahake Gorge but "initial indications are that there have been serious injuries", police said.

The former gold mining area alongside the Ohinemuri River is popular with weekend walkers and explorers.

Police were called to the crash on State Highway 2 near the intersection of School Rd,at 2.20pm.

The highway was closed, which meant a diversion involving significant additional travel time for anyone driving through the area, police said.

"Motorists are advised to avoid the area and consider delaying travel, if possible."